ON ITS EXTEEIOE. VOLCANOES. 413 



active, while the more inland ones are extinct or 

 appear approaching extinction. Sometimes persons 

 have thought that they could recognise within one 

 and the same range of volcanoes, an increase or de- 

 crease of eruptive activity in a definite direction, but 

 the phenomena which are sometimes seen of a re- 

 awakening after long periods of tranquillity render any 

 such recognition very insecure. 



As, owing either to the absence or disregard of well- 

 assured determinations of position, both of the volcanoes 

 themselves and of the nearest points on the sea-shore, 

 there have been many inexact statements respecting the 

 distance of phenomena of volcanic activity from the 

 sea, I give here the following statements in geographical 

 miles (sixty to an equatorial degree). In the Cordil- 

 leras of Quito, Sangay, with its unintermitting activity, 

 is on the easternmost and most distant range, but yet it 

 is only 112 geographical miles from the sea. Very well 

 educated monks of the missions to the Andaquies 

 Indians on the Alto Putumayo have assured me, that 

 on the Upper Eio de la Fragua a tributary of the 

 Caqueta east of the Ceja, they have seen smoke issue 

 ( 565 ) from a not very high conical mountain, of which 

 the estimated distance from the sea was 160 miles. The 

 Mexican volcano of Jorullo, upheaved in September 

 1759, is eighty-four miles from the nearest point of the 

 sea-coast (Kosmos, Bd. iv. S. 339 346, present volume, 

 pp. 294 302); the volcano of Popocatepetl is 132 

 miles from the sea ; an extinct volcano in the eastern 

 cordillera of Bolivia, near S. Pedro de Cacha, in the 

 valley of Yucay (present volume, p. 277), is above 180 

 miles ; the volcanoes of the Siebengebirge near Bonn, 



